Water cooled marine exhaust systems have been previously employed to generally good effect, but have nevertheless possessed certain operational deficiencies. Prior exhaust tips have included various flapper configurations that are typically positioned downstream of a point at which cooling water flow mixes with exhaust gasses. Under normal operation, such positioning of exhaust flappers works well, but issues may arise upon generation of excessive heat levels within the exhaust systems.
In particular, flappers in such systems are often provided with sealing elastomeric, i.e., rubber, material along the edges of the perimeter of the flapper. With continued presence of excessive heat, as for example, from prolonged absence or reduction of cooling fluid, such elastomeric seals may become damaged to the point that direct metal-to-metal contact between the flapper and internal surfaces of the exhaust tips may occur. Such metal-to-metal contact may easily result in significant damage to the flapper as well as the exhaust tip. Additionally, such metal-to-metal contact often results in excessive noise generation during certain operational phases of the marine engine.
Various patents are known concerning marine exhaust related subject matter, including for example Zelinski U.S. Pat. No. 7,104,359 entitled “Muffler having a baffle with angled plates;” Zelinski U.S. Pat. No. 7,013,565 entitled “Removable collector for liquid cooled exhaust;” Zelinski U.S. Pat. No. 6,609,590 entitled “Exhaust system having angled baffle;” and Beson et al. U.S. Pat. No. 6,397,589 entitled “Exhaust pipes and assemblies.” The disclosures of all the patents cited herein are hereby incorporated by reference for all purposes.
In light of such deficiencies recognized herewith in the known exhaust tip flapper configurations, it would be desirable to provide a flapper configuration that avoids such heat damage, and provides possibilities for reduced noise generation.
While various configurations of marine exhaust flapper arrangements have been developed, no design has emerged that generally encompasses all of the desired characteristics as hereafter presented in accordance with the subject technology.